I saw a show on TV about prisons. They mentioned this style originated in prisons as a way to advertise to other men that the wearer is available for sex.
“...this style originated in prisons...”
Yes, it originated in prison, around 30 -35 years ago. But it wasn’t (then) a sexual signal. It was a way of creating a pouch under the crotch as a place to hide contraband (such as drugs or weapons) where the guards would be reluctant to search (frisk). It got more extreme as time went on.
I understand that in California prisons, it was also a way of distinguishing between the black gangs and the Mexican/Chicano gangs; the blacks wore their prison issued uniforms loose and baggy while the Hispanics wore theirs tailored and pressed..